The Future of Power, Unplugged

Duke University researchers developed a device that can send wireless power over distances larger than the device itself.

People have long aspired to develop wireless power technology. The development of the practical application, however, has been slow and limited, producing devices that send weak signals only in very close proximity.

Engineer Nikola Tesla prophesied the ability to transfer large amounts of energy at great distances, and several Duke University researchers believe the secret to Tesla's dream lies in using a "superlens" to transfer energy via low-frequency magnetic fields. These researchers at the Pratt School of Engineering with the Toyota Research Institute of North America developed such a device, which uses structured power coils that "shoot" power to receiving coils approximately one foot away. The technology compares favorably with competing prototypes in intensity and in range.

"For the first time we have demonstrated that the efficiency of magneto-inductive wireless power transfer can be enhanced over distances many times larger than the size of the receiver and transmitter," said Yaroslav Urzhumov, an adjunct assistant professor in the Duke's electrical and computer engineering department, in a university press release. "This is important because if this technology is to become a part of everyday life, it must conform to the dimensions of today's pocket-sized mobile electronics."

Low-frequency magnetic fields are safer than electrical fields to both humans and their devices. The researchers point out that the Federal Communications Commission currently approves the use of magnetic fields in medical imaging that are far stronger than those used by their "superlens" prototype. Since wireless power will increasingly be introduced to buildings (after all, people spend about 90 percent of our lives indoors), architects should monitor this development closely. How should such technology be integrated with architecture, and what are its safe limits for operation? Moreover, what design opportunities does wireless power suggest? Will we eventually be completely untethered, with no more need for pesky cords and cables?

Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.